How to use Vector or other ArrayList etc to store my JTree??

Question

How to use Vector or other ArrayList etc to store my JTree??
Dear friends,
I have following I posted before, but not get satisfactory answer, so I modify and repost again here.
I have following code can add classes and students in the JTree,
in class Computer Science, it has student Bill Brien,
in Math, no,
Then I I add Student Nancy, Laura, Peter into Computer Science Class,
add AAAA, BBB, CCC into Math class,
I create a new class called Chemistry, then I add DDD int Chemistry;
so this JTree is dynamically changed,
[1]. How can I dynamically save my current JTree with all above tree structure and its nodes in a Vector or ArrayList(not sure which one is best)??
see code below:
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
public class ModelJTreeTest extends JFrame {
  private JTree tree;
  private DefaultTreeModel model;
  private DefaultMutableTreeNode rootNode;
  public ModelJTreeTest() {
    DefaultMutableTreeNode philosophersNode = getPhilosopherTree();
    model = new DefaultTreeModel(philosophersNode);
    tree = new JTree(model);
    JButton addButton = new JButton("Add Class/Students");
    addButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
        addPhilosopher();
    JButton removeButton = new JButton("Remove Selected Class/Students");
    removeButton.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent event) {
        removeSelectedPhilosopher();
    JPanel inputPanel = new JPanel();
    inputPanel.add(addButton);
    inputPanel.add(removeButton);
    Container container = getContentPane();
    container.add(new JScrollPane(tree), BorderLayout.CENTER);
    container.add(inputPanel, BorderLayout.NORTH);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(400, 300);
    setVisible(true);
  private void addPhilosopher() {
    DefaultMutableTreeNode parent = getSelectedNode();
    if (parent == null) {
      JOptionPane.showMessageDialog(ModelJTreeTest.this, "Select Class", "Error",
          JOptionPane.ERROR_MESSAGE);
      return;
    String name = JOptionPane.showInputDialog(ModelJTreeTest.this, "Add Class/Students:");
    model.insertNodeInto(new DefaultMutableTreeNode(name), parent, parent.getChildCount());
  private void removeSelectedPhilosopher() {
    DefaultMutableTreeNode selectedNode = getSelectedNode();
    if (selectedNode != null)
      model.removeNodeFromParent(selectedNode);
  private DefaultMutableTreeNode getSelectedNode() {
    return (DefaultMutableTreeNode) tree.getLastSelectedPathComponent();
  private DefaultMutableTreeNode getPhilosopherTree() {
    DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode("Students");
    DefaultMutableTreeNode ancient = new DefaultMutableTreeNode("Computer Science");
    rootNode.add(ancient);
    ancient.add(new DefaultMutableTreeNode("Bill Brian"));
    DefaultMutableTreeNode math = new DefaultMutableTreeNode("Maths");
    rootNode.add(math);  
    DefaultMutableTreeNode physics = new DefaultMutableTreeNode("Physics");
    rootNode.add(physics);
    return rootNode;
  public static void main(String args[]) {
    new ModelJTreeTest();
}the actual Tree dynamically created somehow looks like following:
                         |            1.Peter
                         |---CS---    2. Nancy
                         |            3. Laura
                         |            4.Brian
                         |
Root(University): -------|---Math- 1.AAA
                         |            2.BBB
                         |            3.CCC
                         |
                         |
                         |---Chemistry- 1. DDDThanks a lot
Good weekends

Answer 1

you can't directly store a tree in a list.Ummm... Just to be contrary... Yes you CAN store a tree in a table.... In fact that's how the windows file system works.
Having said that... you would be well advised to investigate tree data-structures before resorting to flattening a tree into a list.
So... Do you have a specific requirement to produce a List? Your umming-and-erring about Vector vs ArrayList makes it sound like you're still at the stage of choosing a datastructure.
Cheers. Keith.